In the manufacture of polysiloxane-treated tissues, the polysiloxane material to be applied to the tissues can be provided as an aqueous emulsion. For purposes of product safety, it is necessary that the emulsion contain a preservative which is effective for inactivating any microorganisms which may be introduced into the emulsion prior to its use during manufacturing of the treated tissues. Preservative efficacy tests were conducted to determine if a particular preservative was performing adequately. It has been discovered that for certain polysiloxane materials which are particularly useful for treating tissues, the preservatives ordinarily used for such emulsions are insufficient. More specifically, the polysiloxane emulsions will have a very limited window of utility from the time of synthesis to the time of application to the tissue because of the growth of noxious microorganisms in the emulsions. Although preservatives are added to the emulsion by the manufacturer, generally those have been found to be of limited value in preventing the growth and proliferation of microorganisms. Because tissue products may be used to directly contact skin around body orifices where the potential for transfer of materials from the tissue to the consumer may constitute a concern, it is generally good practice to reduce contamination of the tissue in every possible way.
In addition, of course, preventing the growth and proliferation of microorganisms in the polysiloxane emulsion will also increase the useful shelf life of the product and prevent off-color, off-odor or destruction of the emulsion. Many preservatives have been tried, but many of these did not provide adequate preservation. Others were ruled out for reasons related to manufacturing or user safety considerations.